Je is a preposition without a defined meaning. The original intent was that je be used in all abstract situations, for which another preposition didn't exist. For that reason, early Esperanto speakers used je very frequently. Now, je is used much less, and it mainly shows time of day and measure. Generally, je should be avoided when a better alternative exists.
The N-ending can often be used instead of je, especially for measure and point in time.
Time of day and other points in time
- Ni prenos la buson je dudek (minutoj) antaŭ la deka (horo). - We will take the bus at twenty to ten.
- Tio okazis je Pasko. - That happened at Easter.
- Je la lasta fojo mi permesas al vi fari tion. - For the last time I'll allow you to do that. (Note that Esperanto uses the present tense here whereas English tends to use the future.)
Measure
- Vi certe estas je duono da kapo pli alta ol mi. = ...duonon da kapo pli alta ol mi. - You're certainly taller than I by half a head. =...half a head taller than I.
The N-ending is ordinarily used to show measure.
Lack, abundance, and longing
-
Ĝi estas libera je mankoj. - It is free of faults.
Or ...de mankoj
- Abram estis tre riĉa je brutoj, arĝento, kaj oro. - Abram was very rich in cattle, silver and gold.
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Glaso da vino estas glaso plena je vino. - A glass of wine is a glass full of wine.
Or ...plena de vino
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Mi sopiras je mia perdita feliĉo. - I sigh for my lost happiness.
Or ...mian perditan feliĉon / ...al mia perdita feliĉo.
State of body or mind
- Ili suferas je astmo. - They suffer from asthma.
- Ŝi gravediĝis je ĝemeloj. - She got pregnant with twins.
- Li malsaniĝis je profunda melankolio. - He became ill with profound melancholy.
Part of the body affected by hold, touch, sickness, etc.
-
Li kaptis min je la brako. - He caught me by the arm.
Je la brako indicates my arm. You can also say ĉe la brako. To indicate his arm (which he uses to catch me), we use per: Li kaptis min je la maldekstra brako per sia dekstra mano.
- Li estas malsana je la brusto. - He has a chest condition.
Various fixed expressions
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Ŝi kredas je Dio. - She believes in God.
Kredi je iu or je io = "to believe that someone or something really exists". Kredi ion, al io, pri io = "to believe that that is true". Kredi al iu = "to believe that this person is telling the truth".
- Je mia miro la afero sukcesis. = La afero sukcesis, kio mirigis min. - To my astonishment the matter succeeded. = The matter succeeded, which astonished me.
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Mi vetis kun ŝi je dek dolaroj. - I made a bet with her for ten dollars.
The winner of the bet will win the ten dollars. You can also use pri.